A reference concept for ADS accelerators

Accelerator Driven Systems (ADS) for transmutation of nuclear waste require multi-megawatt power proton accelerators of exceptional reliability. A study for such a machine has been recently performed as part of the FP5 EC contract PDS-XADS, 'Preliminary Design Study of an Experimental ADS'. A reference solution, based on a linear superconducting accelerator with its associated doubly achromatic beam line has been worked out up to some detail. For high reliability, the design is intrinsically fault tolerant, relying on highly modular 'derated' components associated to a fast digital feedback system. Operational aspects like maintenance and radioprotection were investigated, a consolidated budget calculated, and a roadmap given for the remaining R and D and construction. The present paper gives a short review of the established facts and findings. (author)